Loading pasty solids



Patented Mar. 10, 1942 LOADING PASTY SOLIDS Walter 0. Sneliing,Allentown, Pa., asslgnor to Trojan Powder Company, Allentown, Pa.

No Drawing. Application April Serial No. 391,213

6 Claims.

This invention relates to loading of pasty solids and has for itsprincipal object the provision of a method of so loading such materialas to in-- crease its loaded density. A specific object of the inventionis to charge 80-20 amatol into a shell or bomb to a density as great asis possible with a 5050 amatol which may be poured or cast into theshell cavity.

Amatol is the general name for an explosive consisting of ammoniumnitrate and trinitrotoluene in various percentages, frequently in equalparts, this explosive then being known as so -o amatol. Since an amatolcontaining as little as one-filth of trlnitrotoluene can be detonatedfull eilectiveness it would be highly desirable to substitute suchtill-20 amatol tor the more common till-5o amatoi except for theappreciable differences in gravity.

When. amatol is formed oi equal parts of the two ingredients it can bepoured into a shell in just the same way that the straight TNT can beloaded and therefore can have a high density whereas amatol containing agreater proportion oi ammonium nitrate must always be extruded, tampedor packed into the cavity as a hot pasty solid rather than as a flowingliquid because it does not become a liquid at temperatures or to" abovethe melting point of TNT at 302 C. id therefore must be into the shelloi oi eque ,"ts oi" lnlmonium nitrate and, triniltrotoiuene as high as1.55 whereas the amatol having tour parts oi ammonium nitrate to one oflll'l can be given a loading density of me only with difitlculty. Thisof course means that the total weight of the 80-20 explosive that can beloaded into a shell is almost a tenth less than is possible with theEvil-50 amatol. The bulk or loading density of titamatol is lowerbecause the ammonium nitrate crystals do not melt at this temperaturerange, and there is not enough fluid TNT to flow into the porous spacesand fill them. When the density of the solid crystals is considered,that the particular cavity to be filled. I have found it very convenientto form the particles or grains into small round spheres or pelletsparticularly since these pellets can readily be made in available pelletpresses, using a pressure of say two tons per square inch. By usingpellets of relatively small size the charge can more readily be loadedand the transfer of heat from the pellets which may be at roomtemperature or may be H chilled to any desired degree will not take upall of ammonium nitrate (1.72) is slightly more favorable than that ofTNT (1.65), hence the basic soundness of the idea of highly compressingthe material into pellets.

My method contemplates treating any material the heat of the hottermatrix material until loaded in place.

In the form of my invention in which I am most interested the materialto be loaded is an amatoi in which the major portion of the mixture isammonium nitrate. When four parts of ammonium nitrate to one part oftrinitrotoluene are heated together at a temperature about equal to theboiling point of water or somewhat less, an amatol. is termed having anapparent density or apparent specific gravity of 115, The amatol thusmade is divided into a chosen proportion, using a major portion as amatrix without luv ther treatme t and treatind the minor portion. whlehmay he little as one iourthz but is prefierezloly from one-third toone-hall the total mix, so as to increase its density to or higher,preferably by pelleting the amatol in a pellet press, using pressurewhich may couveiuently vary as desired from as little as 5,669 poundsper square inch to as much as 30,000 pounds per square inch, thesefigures giving pellets having a density which may vary from 1.50 to 1.65or even slightly higher. The compressed pieces may be of other shapes,such as cubes, lozenges, etc., but I prefer the ball shape.

When the shells are ready to be loaded the major portion of the amatolrunning halt to twothirds of the total mix is warmed to a point at whichthe trinitrotoluene will melt and the mixture becomes a pasty solid. Thecompressed blocks or pellets are now mixed with a hot -20 amatol in itspasty condition, providing a charg- -ing mixture in which the highdensity pellets are each su'rrounded by a matrix of the untreated buthot 80-20 amatol which has a. density of about 1.40. The shells may beloaded in any desired manner with the mixture or by alternate layers ofmatrix and compressed lozenges separately tamped in place. Densitiesrunning from 1.45 to 1.50 maybe obtained with. care, and a shell may beloaded to adensity of 1.55 or even higher under specially favorableconditions.

As an example of effectiveness ofthis manner of loading, the normal loadwhich can be charged into a hundred pound demolition bomb is 50 poundsof 50-50 amatol; with untreated 80-20 amatol the best loading is aboutfour pounds short of this weight because of the difierence in density,while with the present invention a charge of nearly if not fully 50pounds of 80-20 amatol may be loaded.

Up to the date of the present invention it was never known to bepossible to load 80-20 amatol to any density equal to or evensubstantially equal to the density of the poured 50-50 amatol. By theuse of this invention one can load 80-20 amatol not only to a higherdensity than was possible before my invention, but it is possible tomaterially facilitate the loading operation as the time of loading isreduced by the use of compressed blocks or pellets of high densityamatol in the matrix of 80-20 amatol of ordinary density. In general theadmixture of the pellets not only tends to increase the density of themass of amatol, but by the sharing of the heat present in thefreshly-made 80-20 amatol with the earlier made pellets of highlycompressed 80-20 amatol, the cooling of the bomb charge is facilitated,and the length of time that the bomb must remain on the loading fioor inprocess 01 being loaded is considerably shortened. The length of timecan still further be shortened by chilling the pellets before mixingwith the hot amatol orby increasing the size of e the pellets or both.

What I claim is: i

1. The method of increasing the density of a charge of amatol in whichthe percentage of the TNT is less than required to make the amatol aflowing liquid at a temperature within ten or twenty degrees above themelting point of the TNT; which comprises compressing a minor por- 2amuse tion of the amatol into pieces-oi a density in excess of 1.50 at apressure from five to thirty thousand pounds per square inch, mixingsuch pieces with a major portion of the uncompressed amatol atatemperature well above 80.2 C., and charging theemixture while still hotinto the cavity to be filled.

2. The method of charging a shell with amatol in which the percentage ofthe ammonium nitrate is appreciably greater than that of the TNT; whichcomprises compressing from about onefourth to about two-thirds of thecharge to pieces of a density of at least 1.50, heating the uncompressedportion of the charge to a pasty condition to form a matrix, mixing thecompressed pieces with the hot matrix and charging the shell with themixture, whereby to obtain a charge of greater density than if theamatol were loaded into the 'shell entirely as a pasty solid.

3. The process of claim 2 in which the amatol is -20, the compressedportion is from onethird to one-half the charge and is in pellets with adensity of at least 1.50 and the final density of the filled charge isabove 1.45.

4. The method of filling a cavity with a material which is pasty atordinary filling temperatures, which comprises compressing a portion ofthe charge into pieces of solid form with a density above 1.42, warminga portion of the untreated material to form a matrix, mixing the solidcompressed material with the pasty matrix,

and loading the cavity with the mixture while the matrix is still pasty.

5. The method of claim-4 in which the pieces are pellets compressed at apressure greater than two tons per square inch and comprising at leastone-fourth of the filling charge, and. the cooling of the charge isfacilitated by the transfer of heat from the hot matrix to therelatively cool pellets.

6. An ainatol charge comprising a body of amatol, with a density below1.45 having embedded therein a proportion, exceeding onefourth, ofparticles of amatol compressed to a density above 1.45.

WALTER O. SNELLING.

